[Illustration: British Submarine.]
The Germans, wishing to kill off their victims one at a time, were ready for the French and Russian Navies, but not for the British. They had less than forty sea-going submarines when the war began. But nearly four hundred took part, or were ready to take part, before the war was over, while many more were building.
We have already noted the weak points of submarines. They are "tender" because they must be thin. An old collier that couldn't steam faster than you could walk sank a submarine by barging into it, end-on—one can hardly call it ramming. Submarines are slower on the surface than dreadnoughts, cruisers, and destroyers; and, after doing a total of ten or twelve hours under water, they have to recharge their batteries; for they run by oil engines on the surface and by electricity submerged, and the crew would be smothered if the oil engines tried to charge batteries without coming up.
Then, firing torpedoes is not at all like firing big guns. At a range of five miles a shell will still be making 2000 feet a second or 1400 miles an hour. At the same range a torpedo like those used at Jutland would be making only 50 feet a second or 35 miles an hour. Thus shells whizz through the air forty times faster than torpedoes sneak through the water. A torpedo, in fact, is itself very like a submarine, more or less cigar-shaped, and with its own engine, screw, and rudder. Hitting with a torpedo really means arranging a collision between it and the ship you are aiming at. When you and the ship and your torpedo and the water are all moving in different ways you can see that hitting is not so easy. The shorter the range the better. But you cannot see at all unless your periscope, with its little mirror, is high and dry out of the water; and periscopes are soon spotted by a sharp look-out at very short range. The best torpedoes are over twenty feet long and as many inches through, and they will go ten miles. But the longer the range the slower the pace and the less the chance of hitting. The engine is driven by air, which is compressed so hard into the middle of the torpedo that it actually bulges out the steel a tiny fraction of an inch. You may set the air-valve fast or slow, and the torpedo will go accordingly. But if you want to make pretty sure you must get within less than a mile, with the ship's broadside toward you, set the torpedo for the right depth, the right pace to keep it going as fast as possible just long enough to hit, and of course the right aim. Then, if all goes well, the cap, or "war head" of the torpedo, on hitting the ship, will set off the fuse that sets off the tremendous charge of high explosive; and this may knock a hole in the side big enough to drive a street car through. But there are many more misses than hits.
Yet the German and Austrian raiders, mines, and submarines sank fifteen million tons of shipping, which is not far short of a third of all the merchant tonnage in the world; and the submarines sank more than the mines and raiders sank together. (Ships are measured by finding out how many cubic feet of space they contain and counting so many feet to the ton. Thus you get a much better idea of how much shipping a country has by counting in tons rather than by the number of ships; for twenty-five ships of one thousand tons each have only half as much sea-power as one ship of fifty thousand tons.) The British loss was nine millions, half as much again as was lost by all the rest of the world put together. Raiders like the cruiser Emden, or the armed and disguised merchant vessel Möwe, did a great deal of harm at the beginning of the war, as we have seen already. Mines did even more harm, and did it all through. But submarines did most.
Our title "Submarining" means any kind of underwater attack, by mines as well as by torpedoes, so we must take a glance at the mines before coming to the submarines.
Most mines are somewhat like big buoys with little horns all over the top. Each horn ends in a cap which, when hit, sets off the charge. Mines coupled together by a steel rope are more dangerous than two separate mines would be, as they are bound to be drawn in against any ship that strikes any part of the rope. The only safeguard a ship could carry was a paravane. A paravane is made up of a strong steel hawser (rope) that serves as a fender, and of two razor-edged blades that serve to cut the mine-moorings free. It is altogether under water and is shaped like a V, with the point jutting out on the end of steel struts ahead of the bows, the two strokes running clear of the sides, and their ends well winged out astern, where the two sharp blades stand straight up, one from each end. The lines by which mines are anchored were thus guided clear of the ship till they reached the blades, where they were cut. The mines then rose to the surface, where they could be set off at a safe distance. Dragging a paravane through the water made the ship go slow. But that was better than being blown up.
Minefields cannot, of course, be crossed at all. You might as well try to walk over armies of porcupines in your bare feet. Some minefields were very big. One British field ran from the Orkneys right across to Norway, to stop the German submarines from getting out round the north of Scotland. The American Navy did magnificent work at this field, the greater part of which was laid by American, not by British, vessels at the latter end of 1917 and earlier part of 1918. Other minefields blocked the Channel. But here the Germans once played a very clever trick which might have cost the British dear. A British minefield had been laid, some fifty feet deep, to catch submarines without being in the way of vessels on the surface. Two days after it had been secretly laid at night the Nubian, a British destroyer, had her bows blown off on the very same spot. The German submarine mine-layers had crept in by night and laid a shallow German minefield, exactly over the deep British minefield, to catch those who were trying to catch them. That, however, is not the end of the story. Just after the Nubian had been towed into Portsmouth with her bows blown off, the Zulu, a destroyer of the same class, was towed in with her stern blown off. So perfectly were both these vessels built that, when they had each been cut in half, the good halves made an absolutely perfect new destroyer, which, under her compound name of Zubian, did excellent work against the Germans during the famous fights at Zeebrugge and Ostend.
A mine laid by a German submarine blew up the cruiser Hampshire that was taking Kitchener to Russia by way of the Orkneys on the 5th of June, 1916. Kitchener was drowned and only twelve men, who floated in on a raft, were saved. Submarines lurking about at night would sometimes put mines right in the track of vessels. And sometimes swift mine-laying ships on the surface would do even more deadly harm, rolling a hundred mines off a little railway on deck. At other times mines would be loosed from the shore or from ships at anchor, so as to float in among vessels with the tide or down the current of a stream. One of these was tried against the British in West Africa by a German missionary. Others were sent against the French and British vessels in the Dardanelles, sometimes blowing them up.
But the enemy never had it all his own way. British submarines did wonderful work in spite of the mines. Commander Holbrook won the V.C. by feeling his perilous way through five lines of Turkish mines, though the currents were very tricky, and more than once the side of his "sub" actually touched the steel ropes holding the mines to their anchors. When he reached Constantinople he torpedoed and sank the Turkish battleship that was supposed to be guarding these very mines! Then he dived back through the five rows of mines and rejoined the fleet without a scratch.